Electric transmission of power.



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Invention Edward MHewLe tli.

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UNITED STATES PATENT OFFICE.

EDVARD M. HEWLETT, OF SOIIENEOTADY, NEV YORK, ASSIGNOR TO GIEN- ERALELEOTRIO COMPANY, A CORPORATION OF NEV YORK.

ELECTRIC TRANSMISSION oF POWER.

SPECIFICATION forming part of Letters Patent No. 706,559, dated August 12, 1902.

Application iiled November 23, 1901. Serial No. 83,410. (No model.)

T CLU 1077/077@ it "my COMOWW My invention embodies various features of Beit known that I, EDWARD M. HEWLETT, a novelty relating to such a system, which will citizen of the United States, residing at Sehenbe hereinafter more fully indicated. ectady, county of Schenectady, State of New In the accompanying drawings, Figure lis 5 York, have invented certain new and useful a diagram of a general transmission system Improvements in Electrical Transmission of embodying my improvements; and Fig. 2 is Power, (Oase No. 2,309,) of which the followa similar diagram of part of the system, showing is a specification. ing in detail the controlling apparatus at the In transmitting power over long distances several distributing-points or substations. 6o 1o general public annoyance is often occasioned Referring rst to Fig. l, l may represent a by accidents to the transmitting-lines at points source of electrical energy located, for exambetween the source of power and point or ple, at a point adjacent to a waterfall or other points of consumption, and which by reason source of cheap power, and communicating of the outlying position require considerable through the usual forms of apparatus with a i5 time for repairs, during which time of course transmission or distribution circuit 2. This the light or power supplied the consumers is circuit may of course be of any desired charcut olf. In long-distance-transmission sysacter. I have shown by way of example a tritems where high potentials` are employed acphase alternating system. Obviously, howcidents of this character are especially liable ever,`the character or form of the transmitted 7o zo to happen, as the insulation is more difficult energy and the number of wires employed has to maintain and the stretch of linebetween no significance from an inventive standpoint. stations is much longer and more difcult to I have shown the system as supplying two carefully inspect. Besides the public annoysubpoints of distribution, 'commonly called ance by failure of service a danger arises in substations, as 3 and 4, and these stations 75 z5 such systems often from grounded `circuits are connected with the source and with one and liability of people or animals coming in another through duplicate sets of transmiscontact with the dangerously-charged wires. sion-mains, as indicated at 2 2b. These mains It is the object ofmy vinvention to remove are carried over different routes as far apart or at least ameliorate these difficulties, to as practicable with aview to reasonableecon- 8o 3o which end I provide in the region over which omy of installation, and at the several distribenergy is distributed duplicate transmissionuting stations they are cross connected by lines carried to the several subdistributingswitches 5, on either side of which is an autopoints or stations over independent routes as matic switch G, so controlled that in case of an far apart as possible, so that the same disuneven balance of the distributing-mains that 3 5 turbing conditions may not exist in both carrying the heavier load will be automaticroutes at'thevsame time. I provide also at ally cut out. Switches of this character are the subdistributing-points means for elecprovided on each side of each substation in the trically connecting or tying together the two system, so that a defective line is opened in transmission-lines and automatic apparatus the section at Vwhich the defect occurs andthe 9o 4o for disconnecting either side of either line remaining part of the system is unaffected. with respect to the substation in case of ashort Thus in case a short circuit occurred at the circuit, ground, or other serious condition point X between stations 3 and 4. the secwhich would interfere with effective service tion of the line Zabetween such stations would over that line. Thus the several supplied stabe automatically .isolated without great in- 45 tions are connected togetherand to the source crease in the resistance of the transmission or sources by lines approaching the stations system, since all of the parts of the system over dierent geographical paths connected still have the full carrying capacity of the in multiple, and in case of damage to any conductors except the section X. A system part of either route that part is automatically of this kind is sufficiently flexible to admit of roo 5o cut out and rendered dead without interrupthe use of generators at different points in tion of service. the system. For example, another generator l might be attached to the other end of the transmission -line or at some intermediate point, if desired, without interfering with the generator l.

In Fig. 2 I have shown in detail a mode of cutting out any section of the transmissionline which may become disordered. I have shown only one substation 3. Since the arrangements will be precisely alike for all, this will be sufficient. On each side of the station connected in the line I iuterpose switches, a break for each phase of the triphase system shown being employed, as indicated at 6 6lL 6b, and I control the operation of these switches or circuit breakers by means of a relay jointly responsive tothe action of both lines. Two of these relays should be used in a triphase system, so as to permit the line-section to be cut out in case of a short circuit or damage to any phase. I connect a series transformer 7 7L 7b in each of the phases, the secondary of which connects with a coil on a differential relay 8 8 8b, under the joint influence of a transformer in the line 2n and one in the line 2l. Thus so long as both sides of the system are doing their calculated duty the armature of the relay is unaffected; but in case of one side carrying more current than the other, indicating` a local interference at some point, the coil on one side ofthe relay prevails and the armature is drawn toward that coil and closes a contact, including a trip-coil for the circuit-breaker in the overloaded phase and insuring the opening of the disturbed side of the system. A similar outiit is provided for the line 2b, transformers 7, 7e, and 7f being connected in the phases of that line. An exactly similar arrangement is provided on the other side of station 3. Let us suppose that a short circuit exists between two of the Wires to the left of station The extra load imposed on the transformer 7 or 7 increases the attractive force of the relaycoil controlled by said transformer and shifts the relay-tongue to the left-say that of 8- thus energizing tripcoil 9 of the circuitbreaker 6 on the disturbed line, opening the circuit, and cutting out the section disturbed. A similar action occurs with any other line on either side of the station.

When a circuit breaker is tripped and opens one of the phases, the relay having one side killed would immediately reverse and open the corresponding phase on the other side of the system. In order to prevent this, I provide a contact in the trip-circuit governed by the circuit-breaker or relay on the opposite side of the system. For example, trip-coil 9 connects through contacts 10 l0n on the circuit-breaker 6d of the corresponding phase to 6 on the opposite side of the system, and, conversely, trip-coil 91 connects through contacts controlled by circuitbreaker 6. If desired, all the phases may be opened when any one is overloaded, in which ease all trip-coils on one side may be actuated when any phase is out of balance a determinate amount. Such an arrangement is shown in dotted lines. If any relay-armature is shifted to the left by preponderance of pull of a phase in the upper side of the system, all the breakersG 6 6b open. If, on the other hand, it shifts to the right by preponderance of pull of a phase in the lower side of the system, the breakers 6 6u (if will open, the common connections being effected in the one case by dotted Wire l2 and in the other by wire 12, as will be evident on inspection of the drawings.

In case the disturbance occurs between stations the circuit is opened at each station and the section cut out and rendered dead. The service is not interrupted or materially disturbed, since the switches 5, which are normally closed, keep both sets of mains in service on each side of the damaged section, whereas one line of the damaged section is in good condition and may remain so until the damaged section is repaired.

I have shown diagram matically at each station a local source for operating the trip-coils. This may be of any desired character, that shown being a direct current, of one hundred and ten volts, say, furnished by a small direct-current generator l1.

What I claim as new, and desire to secure by Letters Patent of the United States, is

l. A system for transmitting electric energy, comprising duplicate transmissionmains connected in parallel at the substation or local distributing-point, and differential means responsive to both mains for automatically opening the damaged main in ease the two sides become unbalanced.

2. An electrical transmission system coinprisin g a generating-station, a distant distributing-station, multiple transmitting-mains, conductive ties between the multiple mains at one or more points, and a dilferential device at such points controlled by the mains jointly for opening a main Which becomes disproportionately loaded.

3. An electrical transmission system containing multiple transmitting-mains traversing different geographical routes, conductive ties between the different mains at a protected point or points, and means responsive to an unbalancing of the mains for opening the defective main in the region of the disturbance.

4:. An electrical transmission system comprising a source of energy and a distributing system containing duplicate transmittingmains,adierential relay at or near a protected point controlled by the joint effect of the two mains, and a circuit-breaker in each main actuated by the relay when the main in which the circuit-breaker is connected carries a disproportionate load with respect to its companion main.

5. An electrical transmission system comprising a source of energy, duplicate transmitting-mains, one or more substations, conductive ties between the mains at the substa- IOO IIC

tions, relays controlled by the joint effect of the duplicate mains, circuit-breakers at each side of the conductive tie, and connections with the relays for opening the circuit of the disturbed main at that side of the tie in which the disturbance occurs.

G. An electrical transmission system comprising a polyphase alternating-current generator, duplicate distributing-mains traversing diierent geographical routes, conductive ties at dierent points between the termini of the system, circuit-breakers for the different phases on each side of a tie, and differential relays controlled by the joint effect of the duplicate mains at each side of a tie for opening the circuit of a disturbed section of the transmitting-main.

7. An electrical transmission system comprising a polyphase alternating-current generator, duplicate distributing-mains crossconnected by conductive ties at points between the termini of the system, currenttransformers in different phases at or near such ties, and circuit-breakers in each main governed by the joint effect of cooperating transformers in the duplicate mains to open the main which becomes disproportionately loaded.

8. A polyphase transmission system comprising a generator, duplicate transmissionmains cross-connected by metallic ties at points between termini, series transformers in different phases of each main at or near a tie, differential relays controlled by the joint effect of the duplicate mains, and circuitbreakers in each main opened by the relay when the main in which the circuit-breaker is connected is disproportionately loaded.

9. An electrical transmission system comprising a source of energy, and a distributing system containing duplicate transmittingmains, a differential relay at or near a protected point controlled by the joint eiect of two corresponding mains, a circuit-breaker in each main tripped by the relay, and means for disabling the circuit-breaker in the duplicate line when its companion operates.

10. An electrical transmission system comprising a source of energy, and a distributing system containing duplicate transmittingn mains, a dierential relay at or near a protected point controlled by the joint effect of two corresponding mains, a circuit-breaker in each main tripped by the relay, and a contact in each trip -circuit opened when the companion circuit-breaker operates.

In witness whereof I have hereunto set my hand this 22d day of November, 1901.

EDWARD M. HEWLET. lVitnesses:

BENJAMIN B. HULL, MARGARET E. WOOLLEY. 

